package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * 秒杀券 订单唯一ID：时间戳 + 序列号
 */
@Component
public class RedisIdWorker {

    private static final long BEGIN_TIMESTAMP = 1640995200L;       //开始时间戳
    private static final long COUNT_BITS = 32;      //序列号位数

    @Resource
    StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix) {
        //1.时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        //2.序列号
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));

        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //拼接生成
        return timestamp << COUNT_BITS | count;
    }

    public static void main(String[] args) {
        LocalDateTime time = LocalDateTime.of(2022, 1, 1, 0, 0, 0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second= " + second);
    }
}
